The primary weather issue this morning is the continued flooding threat along the middle Texas coast. An additional five to ten inches of rain fell overnight in Corpus Christi. That significant dump of rain resulted in major flooding and a rare flash flood emergency to be issued. The heaviest rains have now moved out of Corpus Christi but it’ll take several hours for flood waters to recede. Travel is not recommended there for the remainder of the morning due to numerous closed roads. The heaviest rains on radar are off-shore this morning and will hopefully remain that way throughout the day. Pockets of moderate to heavy rain are falling across the Coastal Plains and that is where a flash flood watch is in effect. Scattered showers will be possible much of the day across South-Central Texas, the Coastal Plains, and Southeast Texas. I’m optimistically hopeful the heaviest rains will remain just off-shore but some flooding may occur today along the coast.
As daytime heating increases this afternoon we could see isolated to scattered showers and thunderstorms develop in the eastern two-thirds of Texas. Activity would be short-lived in the sense storms would be ‘popcorn summer storms’ and would rain themselves out within 30-45 minutes. This type of activity can produce microbursts and localized gusty winds. I can’t rule out a bit of small hail in the stronger cores as well. The main severe weather focus for this afternoon and evening will be in the northern and eastern Texas Panhandle and Oklahoma Panhandle. The Storm Prediction Center has placed a category 2 severe weather risk north of a line from Dalhart-Amarillo-Childress-Wichita Falls. We do note the small category 3 risk across the northeastern Panhandle as well.
Today’s setup involves a surface low that is projected to be across the western Panhandle this afternoon. That low will slowly push southeast by this evening. A dryline will set up just east of the low and a cold front will be pushing from north to south from Kansas tonight. A strong cap is expected to keep thunderstorm development limited through the afternoon hours. By the late afternoon its possible one or two storms may break the cap and develop in the northern/eastern Panhandle. Should that development occur it would likely become supercellular with very large hail, damaging winds, and the potential for a couple tornadoes. Ingredients may become more favorable for a tornado risk in any sustained supercell in the 6-9 PM time frame in the enhanced risk zone. This is a case where we may only have one or two storms for the late afternoon/early evening hours – but those storms that do form would pack a punch. By this evening a cold front pushing south from Kansas will likely help ignite a cluster of storms across the Oklahoma Panhandle/northern Texas Panhandle. That cluster of storms would move southeast. Depending on the location of said storm cluster it could impact portions of the Texas Panhandle, Western Oklahoma, and perhaps the Red River counties of North Texas. We’ll refine this aspect of the forecast by the afternoon hours when we have a better idea on mesoscale factors.
The aforementioned cold front will be our main player in thunderstorm chances for Tuesday. As the cold front pushes south it’ll encounter an enviornment rich with moisture and strongly unstable. Wind shear values will support an organized convective mode. Severe storms capable of producing large hail and damaging wind gusts will be possible. The Storm Prediction Center has issued a category 3 severe weather risk across the Hill Country and South-Central Texas on Tuesday. Junction, San Antonio, and Austin are included in this enhanced risk zone. A category 2 risk includes the Concho Valley, North Texas, Central Texas, Northeast Texas, East Texas, Southeast Texas, the Brazos Valley, Coastal Plains, and South Texas. The highest coverage of severe storms is expected to be in the enhanced risk zone tomorrow but severe storms will be possible Tuesday afternoon and Tuesday evening in either of the risk zones. Large hail and damaging wind gusts are the main threats along with the potential for heavy rain and flooding. If a cluster of thunderstorms is able to organize tomorrow afternoon in Central Texas the threat for more widespread damaging winds would likewise increase. Weak low-level wind shear and the undercutting nature of the cold front will keep the tornado threat very low.